package com.iw.core.security;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;

import org.springframework.security.access.SecurityMetadataSource;
import org.springframework.security.access.intercept.AbstractSecurityInterceptor;
import org.springframework.security.access.intercept.InterceptorStatusToken;
import org.springframework.security.web.FilterInvocation;
import org.springframework.security.web.WebAttributes;
import org.springframework.security.web.access.intercept.FilterInvocationSecurityMetadataSource;

/**
 * @description 一个自定义的filter， 必须包含authenticationManager,accessDecisionManager,securityMetadataSource三个属性， 我们的所有控制将在这三个类中实现
 * @date 2012-8-15
 */
public class MyFilterSecurityInterceptor extends AbstractSecurityInterceptor implements Filter {

	private FilterInvocationSecurityMetadataSource fisMetadataSource;
	private String deniedPage;

	public String getDeniedPage() {
		return deniedPage;
	}

	public void setDeniedPage(String deniedPage) {
		this.deniedPage = deniedPage;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.springframework.security.access.intercept.AbstractSecurityInterceptor#getSecureObjectClass()
	 */
	@Override
	public Class<?> getSecureObjectClass() {
		return FilterInvocation.class;
	}

	@Override
	public SecurityMetadataSource obtainSecurityMetadataSource() {
		return fisMetadataSource;
	}

	@Override
	public void destroy() {
	}

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		// super.beforeInvocation(fi);源码
		// 1.获取请求资源的权限
		// 执行Collection<ConfigAttribute> attributes = SecurityMetadataSource.getAttributes(object);
		// 2.是否拥有权限
		// this.accessDecisionManager.decide(authenticated, object, attributes);
		FilterInvocation fi = new FilterInvocation(request, response, chain);
		InterceptorStatusToken token = super.beforeInvocation(fi);
		try {
			fi.getChain().doFilter(fi.getRequest(), fi.getResponse());

		} catch (Exception e) {
			request.setAttribute(WebAttributes.ACCESS_DENIED_403, e);
			// Set the 403 status code.
			((HttpServletResponse) response).setStatus(HttpServletResponse.SC_FORBIDDEN);
			// forward to error page.
			RequestDispatcher dispatcher = request.getRequestDispatcher(deniedPage);
			dispatcher.forward(request, response);
			e.printStackTrace();
		} finally {
			super.finallyInvocation(token);
		}
		super.afterInvocation(token, null);
	}

	@Override
	public void init(FilterConfig config) throws ServletException {

	}

	public void setFisMetadataSource(FilterInvocationSecurityMetadataSource fisMetadataSource) {
		this.fisMetadataSource = fisMetadataSource;
	}
}